the Rein-sheath in Plebeiid Blues. 299 



A question to which I cannot suggest an answer is, 

 Why should it be lost so soon as pairing is over? It is 

 no longer of any use, but is it now in any" way injurious? 



Its absence may give more room for the movement of 

 the eggs to the ovipositor, and greater freedom to the 

 actions of the structures involved in the important process 

 of the fertilisation of each ovum. 



The sheath in coridon is 2 mm. in length, 0-5 from back 

 to front, and 0-7 from side to side. It looks as if con- 

 structed of a confused congeries of smooth rounded waves, 

 each ending distally, however, in sharp rounded ends, 

 which are the ends of the actual scales; these have no 

 terminal teeth nor any striatums. Each scale is curiously 

 twisted, so that it is difficult to say what its size and out- 

 line would be, if it could be flattened out; but it is ap- 

 proximately 04 to OG mm. long, 0-1 to 0-15 mm. wide 

 at one-third from the free end, tapering fairly regularly 

 to the attached point; it has a granular appearance, no 

 striatums as ordinary scales or rows of elevations like 

 androconia. The granulations seem to be rather contents 

 of the scale than structure of its walls. Various items of 

 these details will be more easily grasped by reference to 

 the Plates. 



In coridon the sheath is tolerably cylindrical in form, 

 but the two extremities are a little oblique to the main 

 axis. In bellargus it is rather flattened in dorso- ventral 

 diameter, more especially distally, where it is rather 

 widened from side to side, giving it an appearance of a 

 waist with spat hul ate extremity. In icarus it is rather 

 expanded basally, narrows slightly towards the end, where 

 it finishes with a more rapid, somewhat conical narrowing. 

 Astrarche presents a form very similar to that of icarus. 

 The difference between coridon and bellargus is less than 

 my description perhaps implies; the sheath in bellargus 

 could certainly not be described as cylindrical, but that 

 of coridon has a slight terminal flattening, that could 

 hardly however be called spathulate. 



I have verified the presence of the sheath in astrarche, 

 icarus, coridon, bellargus, eversmanni, argyrognomon and 

 damon. Further research will probably demonstrate its 

 presence in all these Plebeiids, but it seemed so desirable 

 to make this correction to my paper as early as possible 

 that I have not waited to carry the matter further. 



This scale cylinder is, in itself, as remarkable as the 



